Large storage tanks, for example four hundred barrel tanks, are used to store various liquids at hydrocarbon drilling and completion sites. The stored liquids can be used for different applications, for example, large amounts of water are used in hydraulic fracturing (fracing) operations, for pre-heating equipment, and in on-site mud tanks during drilling operations.
Storage tanks used on-site are often bare steel and the tanks can freeze in cold environments. Problems occur when the temperature of the stored liquid approaches its respective freezing point. The freezing liquid can expand which can lead to damage of the tank as well as the equipment the liquid is to be delivered through and to (for example: piping, tanks, and downstream equipment). In addition, if the liquid cannot be used because it is frozen, the specific application cannot be performed which will result in down-time at the site.
It is known to use external heating equipment, such as steam heaters, to heat the liquid in the storage tank to keep it above its freezing point. Current methods and systems, however, require many external components, are cumbersome, inefficient and expensive, are difficult to transport, and have problems with the stored liquid freezing between components. Current methods and systems using water boilers have difficulties as the boiler water itself can freeze. This can be overcome by replacing the boiler water with glycol when the boiler is not in use or is transported. This process is onerous, however, as the boiler water can be difficult to drain and it is not always desirable to work with glycol. Existing methods and systems using steam coils and similar technologies are only powerful enough to barely keep the liquid stored in a tank above the freezing temperature. This problem is magnified during periods of high liquid usage and very cold environments.
In some contexts it is desirable to reduce or eliminate the volume of a stored liquid on-site to avoid further required storage and/or transportation of the liquid. Present methods and apparatuses used to reduce or eliminate stored liquids on-site, however, are inadequate.
In addition, it is desirable to prevent/avoid the freezing of sewage within sewage systems to prevent damage to the sewage system and reduce downtime. Present methods and apparatuses used to prevent/avoid the freezing of sewage within sewage systems, however, are inadequate.
Accordingly, there is a need to provide apparatuses and methods for heating a stored liquid that overcomes the short-comings of the prior art.